Control for leveling device



June 17, 1958 M. R. SACKETT CONTROL FOR LEVELING DEVICE Filed April 11, 1955 United States Patent Ofiice CGNTRUL FOR LEVELING DEVICE Manley R. Sackett, Sprague, Wash. Application April 11, 1955, Serial No. 500,383 6 Claims. (Cl. 33-209) This invention is a level-seeking fluid type control for leveling devices.

It is an object of the invention to provide a level sensitive control which is adapted to electrically actuate a leveling device designed to correct the vertical tilt of a mobile machine and maintain the vehicle level.

Another object of the invention lies in the provision of a level-seeking fluid type control for leveling devices including a flow control device which eliminates actuation of the control by reason of the fluid surging therein.

Another object of the invention lies in the provision of a level-seeking fluid type control which includes a manually operable displacement member adapted to adjust the operating surface level of the fluids.

Another object of the invention lies in the provision of a level-seeking fluid type control having spaced dashpots communicating with each other and including a flow control device for regulating the speed of flow of fluid from one dashpot to the other.

A still further object of the invention lies in the provision of a levelseeking fluid type control constructed and arranged'so that the initial movement of the fluid in one direction permits a large volume flow of the fluid and subsequently thereto reduces the flow to a predetermined amount.

Still another object of the invention is to generally improve level sensitive control means for leveling devices of mobile equipment.

These and other important objects of the invention will become apparent during the course of the following description. The nature and advantages of the present invention will appear more fully from the following description and accompanying drawings, wherein a preferred form of the improved invention is shown. it should be understood, however, that the drawings and description are illustrative only and are not intended to limit the in vention except insofar as it is expressed in the claims appended to this specification, and as required in view of the prior art.

in the accompanying drawings forming specification:

Figure l is a view in elevation of my improved levelseelcing fluid type control supported under the platform of a mobile piece of equipment;

Figure 2 is a longitudinal vertical fragmentary cross section ta en through one dashpot and its associated switch and housing;

Figure 3 is a longitudinal vertical fragmentary cross section taken through the manually controlled level adjusting displacement device; and

Figure 4 is a fragmentary horizontal cross section taken at the plane indicated by line 44 of Figure 2.

Referring now in detail to the drawing, I have shown a platform ll? of a mobile piece of equipment, such as a combined harvester-thresher (not shown), which it is desired to maintain in substantially level position regardless of the configuration of the terrain over which the a part of this machine may be traveling. Since the platform 19 is rigid part of the machine, it substantially is equivalent to the frame of the machine, insofar as the present invention is concerned.

A supporting bracket 11, comprising a horizontal support bar 12 and spaced hangers 13-13, is secured as by bolts 14 to the platform 10, and it will be seen that the hangers 13 have longitudinal vertically disposed slots 15 so that the support bar 12 may be adjusted to an accurate horizontal position when the machine is level, as here shown in spaced parallel relationship to the platform, and then secured by bolts 16. To provide clearance for the switch mechanism, the bar 12 is united to the arm 13 by means of a rearwardly extending arm 17.

Secured to the support bar 12 as by upstanding brackets 18 (Figure 2) is a fluid containing conduit 19 which constitutes the levelseeking fluid type control of the present invention. The conduit 19 includes spaced reservoirs or dashpots 2il 2tl, which are interconnected at their lower ends by tubing 21, and it will thus be seen that as the control is tilted in a vertical plane coincident to the dashpots, a level-seeking fluid 22 such as mercury will flow freely from one dashpot to the other.

Since the tubing 21 communicates with the dashpots at their lower ends, obviously the level of the fluid in the dashpots will rise as it flows inwardly thereof. Prcviously floats have been actuated by this fluid level directly for the purpose of actuating an electric switch. However, in the present invention 1 provide a flow control element 23 below the float 24 so that the rising of the level of the fluid 22 is controlled and thereby the movement of the float 24 is controlled.

Since each dashpot is identical with the other, a description of one will suffice. Each of the floats 24 is provided with a centric upstanding pushrod 25 which extends through an aperture 26 formed in a base plate 27 of the housing 23 which encloses the switch 29, here shown to be of the micro-switch type. The switch 29 is provided with a vertically tiltable actuating lever or arm 39 which bears upon the upper end of the push rod 25, and therefore as the float 24 rises the switch is actuated to an on position, and as the float lowers, the switch is returned to the normally open position.

Surrounding the push rod 25 I provide a resilient rubber cup 31, which has a concave upper face and is adapted to bear against the base plate 27 and seal about the opening 26 so that fluid which may possibly pass or flow above the float 24 will not escape through the aperture Intermediate the length of the tube 21, I provide a manually operable displacement mechanism 32, by means of which the operating level of the fluid 22 is controlled and adjustable. It will be seen that the displacement member 32 consists of a housing 33 having a bottom wall 34 through which a minute aperture 35 is formed, communicating the interior of the housing 33 to the tubing 21. Loosely carried in the housing 33, I provide a float 36 and a removable top 37 is provided with a manually operable externally threaded thumb bolt 38 and a conventional locking nut 39. Obviously with the thumb bolt pressing upon the top of the float 36, it may be raised and lowered into the fluid 22 so as to vary the working surface of the fluid 22 in the dashpots 20.

An opening 35 is provided to effect ingress and egress of the fluid 22 and yet be reduced to such an extent that surges in the fluid will not produce an adverse effect on the operating level of the fluid in the dashpots, since it may not flow readily into and out of the displacement device. For example, I have determined that an opening of of an inch operates very effectively in a full sized operating device which is substantially 3 inches long and incorporates a tube 21 which is one-half inch in diameter.

In control mechanisms for leveling devices, it is mandatory that the actuating switches be controlled in such a manner that when the machine is tilted from its level position for any appreciable length of time, the switch will be actuated, but as when the machine supporting wheel drops into a hole and immediately comes out again, such swaying and fluctuations must not affect the control mechanism for the leveling device.

It is therefore obvious that the employment of an unrestricted flow of level-seeking fluid and a common buoyant float will not produce the desired result. Therefore I provide the flow control mechanism 23 which is here shown to include an inverted cage which is removably placed in the dashpot 2t) and has its lower edge seated upon an annular sealing ring 411 which has sufficient planar dimension to have a portion extending within the inside peripheral face of the cage 40. At its upper end the cage 44 is provided with an annular sealing ring 42 having a central opening through which fluid may flow and having a lower beveled face 42a which angles upwardly from the opening to the peripheral edge of the sealing ring.

A flow control element 43 is loosely associated within the cage 40 for vertical reciprocal movement within the cage and dashpot. It is therefore obvious that it will alternately under certain conditions attain extreme opposed upper and lower positions. In each case, the control element 43 seals against the annular sealing ring 42 or 41 and prevents the flow of fluid about the element 43 to insure that said flow must pass through the aperture 44 formed through the control element. This aperture, in the present device, is found to operate satisfactorily when it is A: of an inch in diameter.

The cage 40 is releasably secured in the dashpot 20 by means of a set bolt 45 threadedly engaged through the wall of the dashpot 2t) and impinges against the outer peripheral face of the cage 4% The cage 40 has solid side walls to prevent the flow of fluid therethrough, and any fluid flowing through the cage 40 must pass upwardly therethrough to lift the float 24.

In operation, the control element 43 is made from iron, which has a specific gravity of 7.780, and the fluid employed at 22 is mercury having a specific gravity of 13,580. The iron is therefore seen to be .564 the weight of mercury and will thus float therein. Although the invention is not limited to these particular elements, the ratio of weight of the control element and the fluid is of no little importance to the proper functioning of the invention.

When the conduit 19 is in the level position, the displacement member 32 is adjusted so that the level of the fluid 22 causes the control element 43 to float to a position'where it is disposed contacting the upper sealing ring 42. When the machine tilts and the fluid flows into the dashpot, it can only flow therein in a quantity admitted by the reduced aperture 44 in the control element. At the opposed end, however, the fluid may fall away as rapidly as the fluid may discharge through the tube 21. Since there is no other place for the fluid to go than through the openings 44 and 35 of the displacement member, the level rises in the dashpot 20 and the displacement member 32.

When the machine levels and the conduit 19 is returned to level or tilted in the opposed direction, the fluid may fall away from the raised float 24 rapidly by reason of the control device 43 being carried with the surge of the fluid as it drops in the respective dashpot 20. Thus the switch may turn off very rapidly when the conduit 19 reaches a level position, and yet the flow to turn on the switch for leveling will not be effective until the machine has maintained an ofl-level position for a period of time suflicient for the fluid to flow through the aperture 44 and lift the float 24.

It will thus be seen that rapid changes of the level of the machine will not affect the leveling mechanism, but variations in contour of the ground over which the machine is operating will cause the control to operate.

In actual practice, the floats 24 are made from redwood and coated with a lacquer, and obviously since it is required that the control element 4-3 lower with the surge of the fluid 22, it is necessary that it be made of a material which is not so buoyant that it Will float and remain upwardly against the sealing ring 42 regardless of the surge of the fluid seeking level, but will carry downwardly with the surge of the fluid 22.

If the machine tilts rapidly to such a great extent that the surge carries the control device 43 to the bottom of the cage 40, it seals on the sealing ring 41, and again reduces the flow of the fluid to that which will pass through the aperture 44 and not create a ram effect at the lower end.

Having thus described my invention, I claim:

1. In a control for a leveling device including a levelseeking fluid confined in a conduit; a dashpot communicating with said conduit, an inflexible apertured flow control disc reciprocally disposed in said dashpot and floatable on said fluid; and an annular sealing ring in said dashpot above said disc and adapted to cooperate with said disc for precluding flow of said fluid around the edges of said disc when the disc is floated to contact said ring, whereby after its initial ingress surge the level-seeking fluid flows through the aperture of said disc at a rate controlled thereby.

2. In a level-seeking fluid type control for a leveling device, a dashpot adapted to receive fluid flowing upwardly therein to actuate said control, a rigid flow control element vertically reciprocable within said dashpot and adapted to move by means of the surge of said fluid; means limiting the reciprocal movements of said control element at the extreme raised position effected by ingress of said fluid, whereby the free flow surge of said fluid is limited; and means adapted to effect flow of a reduced quantity of fluid from one side of said control element to the other when the control element is stationary in its extreme raised position.

3. In a level-seeking fluid type control for a leveling device, a conduit through which said fluid flows alternately in opposed directions; a rigid flow control element reciprocable within said conduit and adapted to move by means of the surge of said fluid; means limiting the reciprocal movements of said control element alternately at extreme opposed positions whereby the free flow surge of said fluid may be limited; and means adapted to effect flow of a reduced quantity of fluid from one side of said control element to the other when the control element is stationary in one of its two extreme positions.

4. In a level-seeking fluid type control for a leveling device; a dashpot adapted to receive fluid flowing upwardly therein to actuate said control; a rigid flow control element vertically reciprocable within said dashpot and adapted to move by means of the surge of said fluid; means limiting the reciprocal movements of said control element alternately at extreme opposed positions whereby the free flow surge of said fluid may be limited; means adapted to effect flow of a reduced quantity of fluid from one side of said control element to the other when the control element is stationary in one of its two extreme positions; and a switch actuating float disposed in said dashpot spaced above said flow control element, whereby the fluid flowing beyond said control element raises said float.

5. A control for a leveling device comprising a fluid conduit including a pair of spaced dashpots operably interconnected at substantially their lower ends; a levelseeking fluid in said conduit and adapted to surge alternately into the dashpots as the control is rocked in a vertical plane coincident to said dashpots; a confining cage removably secured in the dashpot and adapted to pass fluid flowing therethrough; a rigid apertured flow control element confined for limited reciprocal movement in said cage; annular sealing rings at the upper and lower extremes of said cage and adapted to associate with said flow control element to prevent flow of fluid thereby when disposed in the extreme positions, whereby reduced flow of fluid may pass through the apertured flow control element from one side to the other after the initial surge thereof; a float in each said dashpot adapted to be actuated by inflow of said fluid above said flow control e1ement at a speed proportional to the flow therethrough; and a switch actuated by movements of each said float.

6. In a level seeking fluid type control for leveling devices, a dashpot comprising a housing adapted for corn munication with the balance of said control so that fluid flowing into said dashpot will rise therein; a flow control element adapted to control flow of fluid thereby into said dashpot, floatable on said fluid and vertically reciprocable in said dashpot; said flow control element having an aperture therein to efi'ect flow of fluid therethrough at a pre- Git determined rate of flow; means limiting vertical movement of said flow control element and adapted to seal the marginal edges of said element with the dashpot at the upper limit of movement; and a switch actuating float disposed in said dashpot above said flow control element, whereby to be raised by fluid at a speed proportional to the rate of flow through said aperture.

References Cited in the file of this patent UNITED STATES PATENTS 2,101,837 Blanchett Dec. 14, 1937 2,438,758 Leach Mar. 30, 1948 2,489,542 Rosenblum Nov. 29, 1949 2,532,883 Bennett et a1 Dec. 5, 1950 2,716,169 Hanson Aug. 23, 1955 2,728,355 Dahl Dec. 27, 1955 FOREIGN PATENTS 372,286 Great Britain May 2, 1932 

